Muzzle Device for Firearm Having a Gas Operating System

ABSTRACT

A muzzle device for a firearm comprising a body having a barrel mounting portion and a combustion gas receiving portion, wherein the barrel mounting portion is arranged to mount the muzzle device to a muzzle end of a barrel of the firearm such the combustion gas receiving portion of the muzzle device extends distally from the muzzle end of the barrel, and wherein the combustion gas receiving portion is arranged to capture combustion gas from the barrel of the firearm and provide the combustion gas back to a receiver of the firearm through a combustion gas return tube.

FIELD

The present disclosure relates to relates to firearms, and more particularly relates to gas operated semi-automatic and automatic firearms.

BACKGROUND

Certain semi-automatic and automatic firearms, such as the family of AR-15/M-16 firearms, may operate with a direct gas impingement system, which may be understood as a type of gas operation system.

The direct gas impingement system directs hot propellant combustion gas from a fired cartridge directly to a bolt carrier or slide assembly to cycle the action of the firearm. More particularly, propellant combustion gas from the barrel of the firearm travels through a combustion gas outlet port formed in the barrel, and subsequently into a combustion gas return tube which delivers the propellant combustion gas into the upper receiver of the AR-15/M-16 firearm during operation. Propellant combustion gas is vented into the upper receiver as the bolt carrier assembly is driven aft and separates from the combustion gas return tube.

Unlike gas piston operated firearms, direct impingement does not require a separate gas cylinder, piston, and operating rod assembly. By having high-pressure propellant gas act directly upon the bolt and carrier, the AR-15/M-16 firearms may be provided with lower weight and lower cost than a gas piston operated firearm.

Unfortunately, one problem of the direct gas impingement system is that the firearm becomes fouled more quickly. The venting of the propellant combustion gas becomes a problem because the propellant combustion gas carries contaminates such as vaporized metals, carbon and gaseous residues which may contact cooler operating parts of the firearm and condense thereon. The deposits may then increase friction on the bolt's camming system, which may lead to jamming.

As a result, thorough and frequent cleaning of the upper and lower receivers of AR-15/M-16 firearms is required to better ensure reliability. Furthermore, components of the direct gas impingement system outside the receivers, such as the combustion gas outlet port of the barrel, the combustion gas block and the combustion gas return tube used to deliver the combustion gas into the receiver area, must also be thoroughly cleaned. When these components, certain of which may be difficult to access and clean, become constricted over time, such may result in a lower gas pressure acting on the bolt and carrier which may be insufficient to cycle the action of the firearm, and once again result in jamming.

In addition to the combustion gas outlet port on the barrel becoming fouled, another problem with the AR-15/M-16 firearms has been the specific location of the combustion gas outlet port for the direct gas impingement system to operate properly. The direct gas impingement system of AR-15/M-16 firearms may be understood to have been originally designed for a rifle length barrel having a barrel length of about 20 inches. The barrel includes a combustion gas outlet port formed at about 12.5 inches from the receiver, leaving a barrel length of about 7.5 inches after the combustion gas outlet port, which may be understood as the gas-port-to-muzzle length of the barrel. With the foregoing arrangement, the pressure of the combustion gas passing through the combustion gas outlet port to cycle the action of the AR-15/M-16 rifle peaks in a range of 20,000 to 25,000 psi.

Over the years, the AR-15/M-16 barrel has gotten shorter as manufacturers have sought to configure the AR-15/M16 rifle to fit different end user needs, such as by providing both carbine and pistol versions. Unfortunately, shortening the barrel of the AR-15/M16 firearms and changing the location of the combustion gas outlet port results on changing the operation of the direct gas impingement system. The placement and size of the combustion gas outlet port, as well as the length of the barrel between the combustion gas outlet port and the terminal (muzzle) end of the barrel, i.e. the gas-port-to-muzzle length, are an integral part of the operating system design.

More particularly, the distance of the combustion gas outlet port from the firing chamber, along with the diameter of the barrel interior, the charge of the cartridge and the size of the gas port, largely determine the combustion gas pressure entering the combustion gas outlet port as the projectile passes the outlet port. Furthermore, the distance of the combustion gas outlet port from the firing chamber and the distance of the gas path back to the bolt carrier determines the initial gas timing, while the distance from the gas outlet port to the end of the barrel, i.e. the gas-port-to-muzzle length, determines the duration of the gas system pressure.

Thus, given that combustion gas pressure drops as the projectile travels down the barrel, if the combustion gas outlet port is placed too far aft in the barrel, the combustion gas pressures may be greater than necessarily to cycle the action, and may result in premature wear and other damage to the firearm. On the other hand, if the combustion gas outlet port is placed too far down the barrel, the combustion gas pressures may not be sufficient to cycle the action, or of long enough duration (combustion gas pressure in the barrel drops to zero when the projectile exits the barrel) to cycle the action.

More particularly, the time the projectile remains in the barrel, after passing the combustion gas port, may be referred to as the “dwell” or “dwell time.” Thus, dwell, or dwell time, may be understood as the period that the gas operating system maintains pressure to continue the cycling of the firearm. For a conventional AR-15/M-16, the dwell may be measured from the time the projectile passes the combustion gas outlet port in the barrel to the time the projectile exits the barrel terminal (muzzle) end. Consequently, if the combustion gas outlet port is placed too far down the barrel, resulting in insufficient dwell period, the combustion gas pressures will not have sufficient time to cycle the action.

In contrast to an AR-15/M-16 rifle, for an AR-15/M-16 carbine with a barrel length of about 14.5 inches, the gas-port-to-muzzle length is about 7 inches. As a result, it may be understood that the combustion gas outlet port is about 7.5 inches from the receiver. Such a gas system arrangement may be referred to as a carbine-length gas system, which may be used for barrel lengths of 10 to 18 inches. With the foregoing arrangement, the pressure of the combustion gas passing through the combustion gas outlet port for the AR-15/M-16 carbine peaks in a range of 30,000 to 35,000 psi.

Consequently, all things being equal, as a result of the combustion gas outlet port being moved aft, the combustion gas pressures experienced by the AR-15/M-16 carbine during cycling of the action are significantly increased as compared to the AR-15/M-16 rifle, which may be understood to place greater stress on the AR-15/M-16 carbine, and the potential for greater wear as well as damage.

Moreover, the combustion gas operating pressures are significantly greater as the barrel continues to get shorter. For example, for an AR-15/M-16 pistol with a barrel length of about 7.5 inches, the gas-port-to-muzzle length is about 3 inches. As a result, it may be understood that the combustion gas outlet port is about 4.5 inches from the receiver. Such a gas system arrangement may be referred to as a pistol-length gas system, which may be used for barrel lengths under 10 inches. With the foregoing arrangement, the pressure of the combustion gas passing through the combustion gas outlet port for the AR-15/M-16 pistol peaks in a range of 50,000 to 55,000 psi.

As a result, for AR-15/M-16 pistol with a 7.5 inch barrel, the combustion gas pressures experienced by the pistol during cycling the action may be understood to be significantly greater than even those of the AR-15/M-16 carbine. Furthermore, the dwell may be expected to be significantly lower as the gas-port-to-muzzle length is about 3 inches as opposed to the 7 inch gas-port-to-muzzle length of the AR-15/M-16 carbine. As a result, the AR-15/M-16 pistol must not only cycle with significantly greater operating pressures while cycling the action, but also must cycle the action faster.

Unfortunately, the higher operational pressures associated with the AR-15/M-16 carbine, and more particularly the AR-15/M-16 pistol, may result in the use of heavier duty/heavier weight components. Such may also result in decreased reliability and a decreased useful life of the firearm. Furthermore, the AR-15/M-16 carbine, and more particularly the AR-15/M-16 pistol, may be understood to suffer from greater fouling issues given the shorter length of the gas impingement system.

What is needed is a direct gas impingement system to cycle the action of a shorter barrel firearm, such as the AR-15/M-16 carbine and the AR-15/M-16 pistol, at lower pressure/forces which results in placing less stress on the firearm, as well a gas operating system which offers increased ability to clean the firearm of combustion gas contaminates.

SUMMARY

A muzzle device for a firearm is provided, with the muzzle device comprising a body having a barrel mounting portion and a combustion gas receiving portion, wherein the barrel mounting portion is arranged to mount the muzzle device to a muzzle end of a barrel of the firearm such the combustion gas receiving portion of the muzzle device extends distally from the muzzle end of the barrel, and wherein the combustion gas receiving portion is arranged to capture combustion gas from the barrel of the firearm and provide the combustion gas back to a receiver of the firearm through a combustion gas return tube.

FIGURES

The above-mentioned and other features of this disclosure, and the manner of attaining them, will become more apparent and better understood by reference to the following description of embodiments described herein taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a side view of a firearm according to the present disclosure;

FIG. 2 is a front perspective view of the firearm of FIG. 1;

FIG. 3 is a bottom perspective view of the firearm of FIG. 1;

FIG. 4 is a rear perspective view of the firearm of FIG. 1;

FIG. 5 is a top view of the upper receiver of the firearm of FIG. 1;

FIG. 6 is a cross-sectional side view of the upper receiver of the firearm of FIG. 1 taken along line 6-6 of FIG. 5;

FIG. 7A is a close-up cross-sectional side view of the distal end portion of the upper receiver of FIG. 6 bounded by circle B which includes a muzzle device according to the present;

FIG. 7B is a close-up cross-sectional side view of the distal end portion of the upper receiver of FIG. 6 bounded by circle B which includes the muzzle device of FIG. 7A with a projectile and combustion gas therein;

FIG. 8 is a close-up front perspective view of a main body of a muzzle device according to the present disclosure;

FIG. 9 is a close-up rear perspective view of the main body of FIG. 8;

FIG. 10 is a longitudinal cross-sectional view of the main body of FIG. 8;

FIG. 11 is a cross-sectional view of the main body of FIG. 10 taken along line 11-11;

FIG. 12 is a cross-sectional view of the main body of FIG. 10 taken along line 12-12;

FIG. 13 is a close-up front perspective view of an end cap of a muzzle device according to the present disclosure;

FIG. 14 is a close-up rear perspective view of the end cap of FIG. 13;

FIG. 15 is a front view of the end cap of FIG. 13;

FIG. 16 is a cross-sectional view of the end cap of FIG. 15 taken along line 16-16; and

FIG. 17 is a cross-sectional view of a barrel and gas tube assembled with a gas block of the prior art.

DETAILED DESCRIPTION

It may be appreciated that the present disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The invention(s) herein may be capable of other embodiments and of being practiced or being carried out in various ways. Also, it may be appreciated that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting as such may be understood by one of skill in the art.

Referring now to FIGS. 1-4, there is shown a firearm 100 which may include a muzzle device 140 according to the present disclosure. As shown, the firearm 100 may comprise a gas-operated semi-automatic or automatic firearm, and more particularly a direct gas impingement gas-operated semi-automatic or automatic firearm. As explained in greater detail below, with a direct gas impingement gas-operated firearm, the direct gas impingement system may be understood to direct hot propellant combustion gas from a fired cartridge directly to the bolt carrier or slide assembly of the receiver to cycle the action of the firearm.

Even more particularly, firearm 100 may be a member of the family of AR-15/M-16 firearms, which may include the AR-10, AR-15, M16, M16A1, M16A2, M16A3, M16A4, M4, M4A1, CAR-15, etc. Furthermore, firearm 100 may be categorized as a rifle, a carbine, a mid-length or a pistol, particularly depending on barrel length. As shown in FIG. 1, firearm 100 is shown to be an AR-15/M-16 pistol with a shoulder stock, particularly configured to operate with the 5.56×45 mm NATO military cartridge. Other exemplary calibers may include the 5.56/.223 Remington, 300 Blackout, 0.308 Win/7.62×51, 5.45×39, 7.62×39, 458 SOCOM, and 0.50 Beowulf.

As best shown in FIGS. 1 and 3, firearm 100 comprises a receiver which may be sectioned into a lower receiver 110 and an upper receiver 120. The lower receiver 110 includes the fire control group, grip and butt (shoulder) stock assembly. The upper receiver 120 includes the barrel, bolt carrier group, charging handle, sights, gas system and muzzle device.

Referring now to FIGS. 5 and 6, there is shown the upper receiver 120 of firearm 100 including barrel 130 and muzzle device 140 according to the present disclosure.

As best shown in FIG. 7A, barrel 130 of firearm 100 includes a bore 132 defined by barrel wall 133. A distal end stepped portion 134 of the barrel wall 133 decreases in thickness and diameter via a step down such that a narrow (neck) portion 135 is created at the distal end of the barrel 130. As shown, the narrow (neck) portion 135 terminates proximally at shoulder 136. As used herein, it should be understood that the terms “proximal” and “distal” are made in reference to the longitudinal length of firearm 100 with the muzzle device 130 being at the distal end of the firearm 100, and the butt/stock being at the proximal end of the firearm 100.

A muzzle device 140, which extends distally relative to the barrel terminal (muzzle) end 137, mounts to firearm 100, particularly the barrel 130 thereof. As shown in FIG. 7, as well as FIGS. 8-16 which provide additional views, muzzle device 140 comprises a hollow body 141 which, as shown, may further comprise a main body 142 and an end cap 180. Thus, it should be understood that while body 141 may be shown as two separate pieces particularly provided by main body 142 and end cap 180, body 141 may alternatively be formed as a single unitary (monolithic) piece. Body 141, and more particularly main body 142 and end cap 180, may be fabricated from a suitable gun metal.

Body 141 comprises a barrel mounting portion 144 and a combustion gas receiving portion 156. As such, barrel mounting portion 144 mounts the muzzle device 140 to the barrel terminal (muzzle) end 137 of a barrel 130 of the firearm 100 such that the combustion gas receiving portion 156 of the muzzle device 140 extends distally from the barrel terminal (muzzle) end 137 of the barrel 130.

As shown, barrel mounting portion 144 is provided by main body 142. Barrel mounting portion 144 is adapted to removably connect muzzle device 140 to barrel 130. As shown, due to the deceased outer size (diameter) of barrel mounting portion 144 relative to combustion gas receiving portion 156, a shoulder 145 is provided with combustion gas receiving portion 156, into which combustion gas return tube 220 extends.

Barrel mounting portion 144 includes a longitudinally oriented barrel mounting bore 146, which more particularly comprises a counter-bore which is defined by sidewall 147 of barrel mounting portion 144, which receives the distal end stepped portion 134 of barrel 130. As shown, the narrow (neck) portion 135 of the barrel 130 connects with the narrow portion 148 of the counter-bore 146 via threaded engagement. More particularly, external (male) threads 138 of narrow (neck) portion 135 of the barrel 130 threadably engage with the internal (female) threads 150 of the narrow portion 148 of the counter-bore 146.

Once the barrel 130 and the barrel mounting portion 144 of the muzzle device 140 are suitably secured and properly oriented to one another, such are secured in position by a removable retaining device. As shown, the removable retaining device comprises a tapered, cylindrical (barrel) retaining pin 152 which is inserted into a tapered, cylindrical through-hole formed by opposing semi-circular recesses 139 and 154 formed in the barrel 130 and the barrel mounting portion 144, respectively. As shown, the opposing semi-circular recesses 139 and 154 are formed transverse to the longitudinal axis L of the barrel 130 and the muzzle device 140.

The barrel retaining pin 152 thereafter holds the barrel 130 and the barrel mounting portion 144 of the muzzle device 140 in stationary, secured position and inhibits the barrel 130 and the main body 142 of muzzle device 140 from rotating relative to one another. More particularly, the barrel retaining pin 152 inhibits the main body 142 of muzzle device 140 from rotating relative to the barrel 130.

As set forth above, muzzle device 140 further comprises a combustion gas receiving portion 156, which is formed by body 141, and more particularly main body 142 and end cap 180. The combustion gas receiving portion 156 is arranged to capture combustion gas expelled from the barrel 130 of the firearm 100 and provide the combustion gas back to receiver, here upper receiver 120 of the firearm 100, through combustion gas return tube 220. The combustion gas is then used to cycle the action of firearm 100. As explained in greater detail below, combustion gas receiving portion 156 comprises an enlarged combustion gas (burn) chamber 157 which is provided by cavity 158 formed in main body 142 and cavity 194 formed in end cap 180. As explained in greater detail below, for the 5.56×45 mm cartridge with a 7.5 inch barrel, the volume of the combustion gas (burn) chamber 157 is in a range of 2 to 3 times greater than the volume of the bore 132 of barrel 130, and more particularly 2.5 times greater than the volume of the bore 132 of barrel 130, with the volume of the combustion gas (burn) chamber 157 being about 0.68 in³ (cu in.) and the volume of the bore 132 of barrel 130 being 0.3 in³ (cu in.).

As shown, counter-bore 146 of barrel mounting portion 144 opens into cavity 158 of main body 142. As such, the bore 132 of barrel 130 is in fluid communication with cavities 158 and 194 of main body 142 and end cap 180, respectively.

Combustion gas (burn) chamber 157 is formed by a longitudinally orientated surrounding (annular) sidewall 160 of the main body 142, which extends to and defines the distal end 162 of the main body 142. Combustion gas (burn) chamber 157 is also formed by a transverse end wall 182 of end cap 180. As shown, the inner contour of the end cap 180 includes an arcuate concave inner gas impingement surface 185 which defines cavity 194, and forms part of the combustion gas (burn) chamber 157. As shown, end cap 180 further includes a center, circular (projectile) orifice 186 which is formed by transverse wall 182, through which a projectile passes upon the firing of firearm 100. For the 5.56×45 mm cartridge, the center (projectile) orifice 186 has a diameter which is in a range of 1.1 to 1.3 times greater than the diameter of the bore 132 of barrel 130, and more particularly 1.2 times greater than the diameter of the bore 132 of barrel 130, with the diameter of the center (projectile) orifice 186 having a diameter of 0.272 inch and the bore 132 having a diameter of 0.223 inch.

End cap 180 removably connects to the main body 142 at the distal end thereof, particularly by a mechanical connection. More particularly, main body 142 and end cap 180 connect by threaded engagement. Even more particularly, external (male) threads 184 on sidewall 181 of end cap 180 threadably engage with the internal (female) threads 164 on sidewall 160 of the main body 142.

The end cap 180 may further include a perimeter circular shoulder 188 which extends distally relative to the transverse end wall 182, which results in a circular recess 192 being formed in the outer contour of the end cap 180. As shown, the bottom of the circular recess 192, which is formed by the outer surface 183 of the transverse wall 182, is planar. The distal end of the peripheral wall may include a plurality of pointed raised projections 190, which may be used to shatter glass.

Along an upper side of the muzzle device 140 (along the top of the firearm 100), the combustion gas receiving portion 156 of main body 142 further includes a longitudinally oriented bore 166, which more particularly comprises a counter-bore, which is formed in the shoulder 145 of sidewall 160 of main body 142.

As shown, counter-bore 166 contains an end cap retaining pin 200, a spring 210 and a combustion gas return tube 220. A shaft 204 of the end cap retaining pin 200 extends through the narrow distal portion 168 of the counter-bore 166, while a head 202 of the end cap retaining pin 200 is retained in the wider proximal portion 170 of the counter-bore 166. A distal end portion of shaft 204 may enter a detent 189 of the end cap 180 to inhibit the end cap 180 from rotating relative to the main body 142.

After end cap retaining pin 200 is inserted in counter-bore 166, spring 210 is then inserted into wider proximal portion 170 of the counter-bore 166, with one end thereof in contact with the head 202 of the end cap retaining pin 200. After spring 210 is inserted into the counter-bore 166, combustion gas return tube 220 is inserted into counter-bore 166 with a distal end of the combustion gas return tube 220 in contact with the opposing end of spring 210.

Combustion gas return tube 220 is adapted to removably connect to muzzle device 140. Once the combustion gas return tube 220 is properly positioned and orientated in counter-bore 166, a transverse through hole formed in the combustion gas return tube 220 aligns with a transverse through hole formed in the main body 142. A removable retaining device such as a removable retaining pin 172 is then inserted into the two holes which holds the combustion gas return tube 220 and the main body 142 in stationary position and inhibits the combustion gas return tube 220 and the main body 142 from separating and rotating relative to one another. More particularly, the retaining pin 172 inhibits the combustion gas return tube 220 from rotating relative to the main body 142. The retaining pin 172 may be threaded, such as that of a screw.

Furthermore, with the foregoing construction, when linear spring 210 is compressed within bore 170, end cap retaining pin 200 provides a removable retaining device mounted in the main body 142 which is urged into detent 189 in end cap 180 by the decompression force of the spring 210. As such, during assembly of end cap 180 to main body 142, end cap retaining pin 200 may first be pushed into bore 168 at the distal end thereof (e.g. by the distal end of a flat screw driver), such that the end cap retaining pin 200 is barely exposed. End-cap 180 may be rotated (e.g. threaded clockwise) on to main body 142. When end-cap 180 has been sufficiently threaded onto main body 142, the retracted position of end cap retaining pin 200 may be released such that the distal end of the end cap retaining pin 200 contacts shoulder 188. Thereafter, with continued rotation of end-cap 180, the end cap retaining pin 200 will be urged into the next detent 189 which passes by the distal end of the end cap retaining pin 200 by the decompression (bias) force of spring 210, thus inhibiting the end cap 180 from further rotating relative to the main body 142.

When it is desirable to remove end-cap 180 from main body 142, end cap retaining pin 200 may then again be held in a retracted position and end-cap 180 rotated (e.g. threaded counter-clockwise) until end-cap 180 separates from main body 142.

Alternatively, the end cap retaining pin 200 and the shape of the detent 189 may be such that when end-cap 180 is rotated onto main body 142, the shoulder 188 of the end-cap 180 forces the end cap retaining pin 200 to retract without need of a separate tool.

As shown, combustion gas return tube 220 includes a combustion gas return tube bore 222 defined by combustion gas return tube wall 224. Combustion gas return tube 220 further includes a combustion gas inlet port 226 formed as a cylindrical aperture located in the wall 224 of combustion gas return tube 220. Combustion gas inlet port 226 is in fluid communication with a combustion gas outlet port 159 formed in main body 142, which is formed adjacent a rear wall 161 of the combustion gas (burn) chamber 157, which is shown to be planar. Moreover, as shown, combustion gas outlet port 159 is actually part of through-bore 174, which permits easily cleaning of gas outlet port 159 when combustion gas return tube 220 is removed from counter-bore 166. Combustion gas outlet port 159 and combustion gas inlet port 226 may have a diameter in a range of 0.100 inch to 0.110 inch and more particularly 0.0.104 inch.

Thus, the combustion gas receiving portion 156 includes a combustion gas (burn) chamber 157 and a combustion gas outlet port 159, with the combustion gas outlet port 159 arranged to receive combustion gas directly from the combustion gas (burn) chamber 157 and provide the combustion gas directly to combustion gas inlet port 226 of the combustion gas return tube 220.

More particularly, the combustion gas receiving portion 156 includes a combustion gas (burn) chamber 157 and exactly two outlets for the combustion gas, with the two outlets provided by the combustion gas outlet port 159 arranged to receive combustion gas directly from the combustion gas (burn) chamber 157 and provide the combustion gas directly to an inlet port 226 of the combustion gas return tube 220, and a projectile orifice 186 arranged at a distal end of the body 141.

As set forth above, firearm 100 may comprise a gas-operated semi-automatic or automatic firearm, and more particularly a direct gas impingement gas-operated firearm in which the direct gas impingement system directs hot propellant combustion gas from a fired cartridge directly to the bolt carrier or slide assembly of the upper receiver 120 to cycle the action of the firearm 100.

More particularly, as shown in FIG. 7B, propellant combustion gas from the bore 132 of barrel 130 is received into combustion gas (burn) chamber 157. Without being bound to a particular theory, it is believed that as soon as projectile 250 clears the barrel terminal (muzzle) end 137, the hot propellant combustion gas, as shown by the arrows, will expand on either side of the projectile 250 to the size of the combustion gas (burn) chamber 157. A portion of the combustion gas may then follow the arcuate surface 185 of end cap 180 and be redirected proximally due to the curvature of surface 185. This may be understood to increase the pressure in combustion gas (burn) chamber 157, along with the dwell.

Due to the pressure in combustion gas (burn) chamber 157, the combustion gas then travels through combustion gas outlet port 159 into combustion gas inlet port 226 and into combustion gas return tube bore 222 of combustion gas return tube 220. As best shown in FIG. 6, combustion gas return tube 220 delivers the propellant combustion gas into the upper receiver 130 of firearm to cycle the action. Propellant combustion gas is vented into the upper receiver 130 as the bolt carrier assembly is driven aft and separates from the combustion gas return tube 220. With the foregoing construction of firearm 100, certain advantages are realized over the art.

With a conventional AR-15/M-16 rifle, shown as firearm 10 in FIG. 17, propellant combustion gas from the bore 32 of barrel 30 travels into a combustion gas outlet port 36 formed the barrel 30. Thereafter, the combustion gas travels into a gas transfer port 44 located in a gas block 40 mounted on top of the barrel 30. From the gas transfer port 44 of the gas block 40, the combustion gas then travels into combustion gas inlet port 56 and combustion gas return tube bore 52 of combustion gas return tube 50. In addition to the gas block 50, the barrel 30 includes a flash hider 60 mounted to the barrel terminal (muzzle) end 37.

In contrast to the prior art, the muzzle device 140 of the present disclosure eliminates the need for a separate gas block 40, as well as a combustion gas outlet port 36 being formed in the wall 34 of the barrel 30 as known in the art, which must be precision drilled and finished. Furthermore, the muzzle device 100 of the present disclosure does not encounter the cleaning concerns encountered with a combustion gas outlet port 36 formed in the barrel 30. As set forth above, propellant combustion gas may be understood to carry contaminates such as vaporized metals, carbon and residues. As such, these contaminates may foul the gas out port 36 formed in barrel 30, which may lead to erosion as well as inadvertent damage to the barrel 30 during cleaning, such as by scratching the barrel rifling or otherwise damaging the bore 32, which both shorten barrel life. In contrast, with the muzzle device 100 of the present disclosure eliminating the combustion gas outlet port 36 formed in barrel 30, there is no risk of damaging the bore 132 in such a similar manner.

Also importantly, muzzle device 100 does not need remain with the firearm 100 during cleaning thereof. In other words, muzzle device 100 may be removed from the barrel 130 to be cleaned, and simply replaced with a second muzzle device 100 while the first muzzle device 100 is thereafter being cleaned. The present disclosure provides for removing muzzle device 140 from firearm 100 by simple mechanical disconnection from the barrel 130 and combustion gas return tube 220.

In contrast, with combustion gas outlet port 36 formed in barrel 30 of a firearm 10 of the prior art, such must generally be cleaned with the remainder of the firearm 10, unless the firearm 10 is substantially broken down to remove the barrel 30. In either case, cleaning gas outlet port 36 formed in barrel 30 of firearm 10 may be understood to take longer than removing and replacing muzzle device 140 on firearm 100. As such, firearm 100 may be made more readily available in emergency situations.

In addition, the amount of contaminates received into the receiver 130 of firearm 100 may be reduced with use of muzzle device 100 as compared to a prior art gas operating system which makes use of a gas out port 36 formed in the barrel 30. Due to the large surface area of the combustion gas (burn) chamber 157, certain contaminates within the combustion gas may collect in the combustion gas (burn) chamber 157 rather than passing through the combustion gas outlet port 159 and combustion gas return tube 220 to receiver 130. Moreover, contaminates which may be captured in may be easily removed from the combustion gas (burn) chamber 157 simply be removing end cap 180 from main body 142 and cleaning the combustion gas (burn) chamber 157.

Furthermore, combustion gas (burn) chamber 157 may also operate as a flash suppressor. While not being bound to a particular theory, rifle flash may be understood to be created by excess powder burning when it comes into contact with air after the projectile leaves the bore of the barrel. As such, a flash suppressor may be understood to reduce the flash which may occur as the projectile leaves the firearm, particularly to protect the shooter's eyesight from a quick change in brightness, thus keeping the target in sight and permitting follow-up shots. With combustion gas (burn) chamber 157, excess power may be trapped in therein, where it may remain until the combustion gas (burn) chamber 157 is cleaned or such burns with sufficient heat.

Moreover, muzzle device 100 may enable the a firearm 100, such as an AR-15/M-16 carbine, and more particularly an AR-15/M-16 pistol, to make use of a longer gas system to reduce the operating pressures during the cycling of the action. For example, muzzle device 100 may enable an AR-15/M-16 carbine to make use of a rifle-length gas system, and my enable an AR-15/M-16 pistol to make use of a carbine-length gas system. Furthermore, the combustion gas (burn) chamber 157 may mediate the pressure spike and smooth out the action thus reducing wear.

With the present disclosure, it has been found that, due to the cross-sectional increase of the combustion gas (burn) chamber 157 as compared to the bore 132 of barrel 130, the longitudinal distance between the combustion gas outlet port 159 and the end cap center (projectile) orifice 186 may be greatly shortened (as compared to the longitudinal distance between the combustion gas outlet port 36 and the barrel terminal (muzzle) end 37 of a traditional AR-15/M-16 of FIG. 17), while maintaining the necessary dwell to operate the firearm 100. Furthermore, the use of combustion gas (burn) chamber 157 has been found to provide a smoother, softer cycling of the action of firearm 100 and mediate the pressure spike of the fired projectile.

In order to provide the necessary dwell for muzzle device 100, after a certain amount of testing, for a AR-15/M-15 5.56×45 mm cartridge and a 7.5 inch barrel, the volume of the combustion gas (burn) chamber 157 was sized to be equivalent to the volume of the bore 32 of a rifle barrel 30 of about 18 inches, such resulting in a total volume equal to that of a 25 inch barrel when the 7.5 inch pistol barrel is added thereto. As set forth above, the volume of the combustion gas (burn) chamber 157 is about 2.5 times greater than the volume of the bore 132 of barrel 130, with the volume of the combustion gas (burn) chamber 157 being about 0.68 in³ (cu in.) and the volume of the bore 132 of barrel 130 being 0.3 in³ (cu in.).

As set forth above, for an AR-15/M-16 pistol with a barrel length of about 7.5 inches, the conventional gas-port-to-muzzle length is about 3 inches, and the combustion gas outlet port is about 4.5 inches from the receiver. Furthermore, the end of the barrel generally includes a conventional flash hider attached thereto, making the overall barrel length about 10 inches.

However, when the muzzle device 140 of the present disclosure replaces a conventional flash hider, the combustion gas return tube 220 is now mounted to the muzzle device 140 and no longer the barrel 130. As such, given that the barrel length about 7.5 inches for an AR-15/M-16 pistol, it is now possible to mount a carbine-length gas system to the AR-15/M-16 pistol, whereby the combustion gas outlet port 159 is now about 7.5 inches from the receiver.

As a result of the combustion gas return tube 220 now being mounted to the muzzle device 140 and no longer to the barrel 130, the gas operational pressures of the AR-15/M-16 pistol are decreased particularly given the combustion gas outlet port 159 is moved distally. As a result, the stress on the firearm 100 during firing and the potential for wear as well as damage are all decreased. More particularly, with use of muzzle device 140, the pressure of the combustion gas passing through the combustion gas outlet port 159 for the AR-15/M-16 pistol drops from a peak of about 50,000 psi to about 20,000 psi, which is comparable to an AR-16/M-16 rifle. Moreover, the gas pressure in the gas return tube 220 going to the bolt may be in a range of 8,000 psi. to 12,000 psi., and more particularly in a range of 9,000 psi to 10,000 psi.

Such a gas pressure in the gas return tube 220 (of 9,000 psi to 10,000 psi.) may be achieved with the foregoing relationship between the combined the volume of the bore 132 of barrel 130 and volume of the combustion gas (burn) chamber 157 and the diameter of the combustion gas outlet port 159/combustion gas inlet port 226 having in a range of 0.100 inch to 0.110 inch and more particularly 0.0.104 inch. The pressure may be measured using any of the known techniques, including the copper crusher method, piezo method and strain gauge method.

While a preferred embodiment of the present invention(s) has been described, it should be understood that various changes, adaptations and modifications can be made therein without departing from the spirit of the invention(s) and the scope of the appended claims. The scope of the invention(s) should, therefore, be determined not with reference to the above description, but instead should be determined with reference to the appended claims along with their full scope of equivalents. Furthermore, it should be understood that the appended claims do not necessarily comprise the broadest scope of the invention(s) which the applicant is entitled to claim, or the only manner(s) in which the invention(s) may be claimed, or that all recited features are necessary.

LISTING OF REFERENCE CHARACTERS

-   100 firearm -   110 lower receiver -   120 upper receiver -   130 barrel -   132 barrel bore -   133 barrel wall -   134 barrel distal end stepped portion -   135 barrel narrow (neck) portion -   136 barrel shoulder -   137 barrel terminal (muzzle) end -   138 barrel external (male) threads -   139 barrel semi-circular recess -   140 muzzle device -   141 body -   142 main body -   144 barrel mounting portion -   145 combustion gas receiving portion shoulder -   146 barrel mounting portion bore (counter-bore) -   147 barrel mounting portion sidewall -   148 barrel mounting portion counter-bore narrow portion -   150 barrel mounting portion counter-bore (female) threads -   152 barrel retaining pin -   154 barrel mounting portion semi-circular recess -   156 combustion gas receiving portion -   157 enlarged combustion gas (burn) chamber -   158 cavity of main body -   159 combustion gas outlet port -   160 main body sidewall -   161 rear wall of combustion gas burn chamber -   162 main body distal end -   164 main body distal (female) threads -   166 combustion gas receiving portion bore -   168 combustion gas receiving portion counter-bore narrow portion -   170 combustion gas receiving portion counter-bore wide portion -   172 retaining pin -   174 through-bore in main body -   180 end cap -   181 end cap sidewall -   182 transverse end wall -   183 outer surface of transverse wall -   184 end cap (male) threads -   185 inner gas impingement surface of transverse wall -   186 end cap center (projectile) orifice -   188 end cap shoulder -   189 end cap detents -   190 end cap projections -   192 end cap circular recess -   194 cavity of end cap -   200 end cap retaining pin -   202 head -   204 shaft -   210 spring -   220 combustion gas return tube -   222 combustion gas return tube bore -   224 combustion gas return tube wall -   226 combustion gas return tube inlet port -   250 projectile 

What is claimed is:
 1. A muzzle device for a firearm, comprising: a body comprising a barrel mounting portion and a combustion gas receiving portion; the barrel mounting portion to mount the muzzle device to a muzzle end of a barrel of the firearm such that the combustion gas receiving portion of the muzzle device extends distally from the muzzle end of the barrel; and the combustion gas receiving portion arranged to capture combustion gas from the barrel of the firearm and provide the combustion gas back to a receiver of the firearm through a combustion gas return tube.
 2. The device of claim 1 wherein: the combustion gas receiving portion includes a combustion gas chamber and a combustion gas outlet port; and the combustion gas outlet port arranged to receive combustion gas directly from the combustion gas chamber and provide the combustion gas directly to an inlet port of the combustion gas return tube.
 3. The device of claim 2 wherein: the combustion gas outlet port is arranged adjacent a rear wall of the combustion gas chamber.
 4. The device of claim 2 wherein: the combustion gas outlet port is part of a through-bore formed in the body.
 5. The device of claim 2 wherein: a distal end of the combustion gas chamber is defined by a transverse wall of the body; and the transverse wall has an arcuate inner surface.
 6. The device of claim 5 wherein: the barrel of the firearm has a bore with a diameter; the transverse wall defines a projectile orifice for a projectile fired by the firearm to exit the muzzle device, the projectile orifice being circular and having a diameter; and the projectile orifice diameter is greater than the bore diameter in a range of 1.1 to 1.3 times the bore diameter.
 7. The device of claim 1 wherein: the combustion gas receiving portion includes a combustion gas chamber and exactly two outlets for the combustion gas; and the two outlets provided by a combustion gas outlet port arranged to receive combustion gas directly from the combustion gas chamber and provide the combustion gas directly to an inlet port of the combustion gas return tube, and a projectile orifice arranged at a distal end of the body.
 8. The device of claim 1 wherein: the body comprises a main body and an end cap.
 9. The device of claim 8 wherein: the main body and the end cap are connected by a mechanical connection.
 10. The device of claim 9 wherein: the main body and the end cap are connected by threaded engagement.
 11. The device of claim 8 further comprising: a retaining device which inhibits the main body and the end cap from rotating relative to one another.
 12. The device of claim 11 wherein: the retaining device comprises a end cap retaining pin mounted in the main body which is configured to be urged into a detent formed in the end cap.
 13. The device of claim 12 wherein: the end cap retaining pin is spring biased by a linear spring.
 14. The device of claim 1 wherein: the body comprises a bore to receive the combustion gas return tube.
 15. The device of claim 1 further comprising: a retaining device which inhibits the body and the combustion gas return tube from separating relative to one another.
 16. The device of claim 15 wherein: the retaining device comprises a combustion gas return tube retaining pin.
 17. The device of claim 1 wherein: the barrel mounting portion is threaded.
 18. The device of claim 1 wherein: the barrel mounting portion comprises a bore to receive a distal end portion of the barrel.
 19. The device of claim 1 further comprising: a retaining device which inhibits the body and the barrel from rotating relative to one another.
 20. The device of claim 19 wherein: the retaining device comprises a barrel retaining pin. 